RESUMO
Human and animal fungal pathogens are a growing threat worldwide leading to emerging infections and creating new risks for established ones. There is a growing need for a rapid and accurate identification of pathogens to enable early diagnosis and targeted antifungal therapy. Morphological and biochemical identification methods are time-consuming and require trained experts. Alternatively, molecular methods, such as DNA barcoding, a powerful and easy tool for rapid monophasic identification, offer a practical approach for species identification and less demanding in terms of taxonomical expertise. However, its wide-spread use is still limited by a lack of quality-controlled reference databases and the evolving recognition and definition of new fungal species/complexes. An international consortium of medical mycology laboratories was formed aiming to establish a quality controlled ITS database under the umbrella of the ISHAM working group on "DNA barcoding of human and animal pathogenic fungi." A new database, containing 2800 ITS sequences representing 421 fungal species, providing the medical community with a freely accessible tool at http://www.isham.org/ and http://its.mycologylab.org/ to rapidly and reliably identify most agents of mycoses, was established. The generated sequences included in the new database were used to evaluate the variation and overall utility of the ITS region for the identification of pathogenic fungi at intra-and interspecies level. The average intraspecies variation ranged from 0 to 2.25%. This highlighted selected pathogenic fungal species, such as the dermatophytes and emerging yeast, for which additional molecular methods/genetic markers are required for their reliable identification from clinical and veterinary specimens.
Assuntos
Código de Barras de DNA Taxonômico , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Bases de Dados de Ácidos Nucleicos , Fungos/classificação , Técnicas de Diagnóstico Molecular/métodos , Micoses/diagnóstico , Animais , Fungos/genética , Humanos , Micoses/microbiologia , Micoses/veterinária , Padrões de ReferênciaRESUMO
The diversity of Trichoderma (Hypocreales, Ascomycota) colonizing leaf litter as well as the rhizosphere of Garcinia macrophylla (Clusiaceae) was investigated in primary and secondary rain forests in Colombian Amazonia. DNA barcoding of 107 strains based on the internal transcribed spacers 1 and 2 (ITS1 and 2) of the ribosomal RNA gene cluster and the partial sequence of the translation elongation factor 1 alpha (tef1) gene revealed that the diversity of Trichoderma was dominated (71 %) by three common cosmopolitan species, namely Trichoderma harzianum sensu lato (41 %), Trichoderma spirale (17 %) and Trichoderma koningiopsis (13 %). Four ITS 1 and 2 phylotypes (13 strains) could not be identified with certainty. Multigene phylogenetic analysis and phenotype profiling of four strains with an ITS1 and 2 phylotype similar to Trichoderma strigosum revealed a new sister species of the latter that is described here as Trichoderma strigosellum sp. nov. Sequence similarity searches revealed that this species also occurs in soils of Malaysia and Cameroon, suggesting a pantropical distribution.
Assuntos
Biodiversidade , Código de Barras de DNA Taxonômico , Microbiologia do Solo , Trichoderma/classificação , Trichoderma/genética , Análise por Conglomerados , Colômbia , DNA Fúngico/química , DNA Fúngico/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Haplótipos , Técnicas Microbiológicas , Microscopia , Dados de Sequência Molecular , Filogenia , Análise de Sequência de DNA , Trichoderma/citologia , Trichoderma/isolamento & purificaçãoRESUMO
Morphological and molecular analyses demonstrate that Coniolariella gamsii and Coniolaria murandii are distinct species. The latter species is validated here as Coniolariella macrothecia. A key to the five species of the genus is provided.
Assuntos
Filogenia , Xylariales/classificação , Dados de Sequência Molecular , Esporos Fúngicos/classificação , Esporos Fúngicos/genética , Esporos Fúngicos/isolamento & purificação , Xylariales/genética , Xylariales/isolamento & purificaçãoRESUMO
Fourty-nine species and strains of filamentous fungi of the genera Acremonium, Bionectria, Clonostachys, Emericellopsis, Hypocrea/Trichoderma, Lecythophora, Monocillium, Nectriopsis, Niesslia, Tolypocladium, and Wardomyces, deposited with the culture collection of the Centraalbureau voor Schimmelcultures (CBS) in Utrecht, The Netherlands, were grown on nutrient agar plates. Organic extracts of mycelia were analyzed after acidic total hydrolysis and derivatization by GC/SIM-MS on Chirasil-L-Val for the presence of Aib (=alpha-aminoisobutyric acid, 2-methylalanine) and DL-Iva (=isovaline, 2-ethylalanine). In 37 of the hydrolysates, Aib was detected, and in several of them D-Iva or mixtures of D- and L-Iva. Non-proteinogenic Aib, in particular, is a highly specific marker for a distinctive group of fungal polypeptides named peptaibols or, comprehensively, peptaibiotics, i.e., peptides containing Aib and displaying (anti)biotic activities. The biotic synthesis of these amino acids by filamentous fungi contradicts the still widespread belief that alpha,alpha-dialkyl-alpha-amino acids do not or rarely occur in the biosphere and, if detected, are of extraterrestrial origin. The abundant production of peptaibiotics by cosmopolitan species of microfungi has also to be considered in the discussion on the occurrence of Aib and Iva in ancient and recent sediments. The detection of trace amounts of Aib in ice samples of Antarctica that are devoid of meteorites might also be related to the presence of Aib-producing microorganisms, being either indigenous psychrophiles, or being transported and localized by mechanisms related to bioaerosols and cryoconites. The presence of microfungi being capable of producing alpha,alpha-dialkyl alpha-amino acids in terrestrial samples, and possible contamination of extraterrestrial materials are pointed out to be of relevance for the reliable interpretation of cosmogeochemical data.
Assuntos
Ácidos Aminoisobutíricos/química , Valina/química , Meio Ambiente Extraterreno , Fungos/química , Cromatografia Gasosa-Espectrometria de Massas , Geografia , Peptaibols/química , Peptaibols/isolamento & purificaçãoRESUMO
Linearity is not considered a prerequisite anymore, and extension of the current definition of 'peptaibiotics' to cyclic, Aib-containing peptides is proposed. Sequences and bioactivities, together with ecophysiological importance of cyclopeptaibiotics and related cyclic tetrapeptides, and their fungal-taxonomic relationships, are discussed.
Assuntos
Peptídeos Cíclicos/química , Animais , Humanos , Peptídeos Cíclicos/farmacologia , Relação Estrutura-AtividadeRESUMO
Three strains of Trichoderma brevicompactum and another four that are closely related to that species (Trichoderma cf. brevicompactum) were analyzed for the formation of polypeptide antibiotics (peptaibiotics) by LC/ESI-MS(n). These isolates were selected because of an antagonistic potential against Eutypa dieback and Esca disease of grapevine and have not yet been investigated for the production of peptide antibiotics. Fully grown cultures on potato dextrose agar were extracted with CH2Cl2/MeOH, and this extract was subjected to SPE using C18 cartridges. The methanolic eluates were analyzed by LC/ESI-MS(n). All strains were found to produce membrane-active alamethicins F30. In addition to that, novel peptaibiotics were detected, namely, 14 12-residue trichocryptins B, 12 11-residue trichocryptins A, 19 11-residue trichobrevins A and B, 6 10-residue trichoferins, and 17 8-residue trichocompactins. These compounds may partially be responsible for the plant-protective action of the producers. Chemotaxonomic considerations also indicated the necessity to introduce another new species that is closely related to T. brevicompactum.
Assuntos
Antibacterianos/biossíntese , Peptídeos/metabolismo , Plantas/microbiologia , Trichoderma/metabolismo , Antibacterianos/química , Cromatografia Líquida de Alta Pressão , Doenças das Plantas/microbiologia , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
Eight strains of Trichoderma species (T. strigosum, T. erinaceus, T. pubescens, T. stromaticum, and T. spirale as well as T. cf. strigosum, T. cf. pubescens) were selected because of their antagonistic potential against Eutypa dieback and Esca which are fungal diseases of grapevine trunks. These isolates were screened for the production of a group of polypeptide antibiotics named peptaibiotics, including its subgroups peptaibols and lipopeptaibols. Fully-grown fungal cultures on potato-dextrose agar were extracted with CH(2)Cl(2)/MeOH, and these extracts were subjected to SPE using C(18) cartridges. The methanolic eluates were analyzed by on-line LC/ESI-MS(n) coupling--a method which is referred to as 'peptaibiomics'. New seven-, ten-, and eleven-residue lipopeptaibols, with N-terminal alkanoyl, and C-terminal leucinol or isoleucinol residues were found and named lipostrigocins and lipopubescins. Furthermore, new 18-residue peptaibols named trichostromaticins and 19-residue peptaibols named trichostrigocins were discovered. One peptaibiotic carrying a free C-terminal valine (or isovaline) named trichocompactin XII was also sequenced. These results corroborate the hypothesis that peptaibiotics might contribute to the plant-protective action of their fungal producers. The data also point out that comparison of peptaibiotic sequences is of limited relevance in order to establish chemotaxonomic relationships among species of the genus Trichoderma.
Assuntos
Antibacterianos/análise , Antibacterianos/farmacologia , Peptídeos/análise , Peptídeos/farmacologia , Doenças das Plantas/microbiologia , Trichoderma/química , Trichoderma/fisiologia , Antibacterianos/biossíntese , Cromatografia Líquida de Alta Pressão , Avaliação Pré-Clínica de Medicamentos , Peptídeos/metabolismo , ProteômicaRESUMO
A list of 254 names of species and two names of varieties in Trichoderma with name or names against which they are to be protected, following the ICN (Melbourne Code, Art. 14.13), is presented for consideration by the General Committee established by the Congress, which then will refer them to the Nomenclature Committee for Fungi (NCF). This list includes 252 species, one variety and one form. Two new names are proposed: T. neocrassum Samuel (syn. Hypocrea crassa P. Chaverri & Samuels), T. patellotropicum Samuels (syn. Hypocrea patella f. tropica Yoshim. Doi). The following new combinations in Trichoderma are proposed: T. brevipes (Mont.) Samuels, T. cerebriforme (Berk.) Samuels, T. latizonatum (Peck) Samuels, and T. poronioideum (A. Möller) Samuels. The following species are lectotypified: T. americanum (Canham) Jaklitsch & Voglmayr, Gliocladium flavofuscum J.H. Miller, Giddens & A.A. Foster, T. inhamatum Veerkamp & W. Gams, T. konilangbra Samuels, O. Petrini & C.P. Kubicek, T. koningii Oudem., T. pezizoides (Berk. & Broome) Jaklitsch & Voglmayr, T. sulphureum (Schwein.) Jaklitsch & Voglmayr and T. virens (J.H. Miller, Giddens & A.A. Foster) Arx. Epitypes are proposed for the following species: T. albocorneum (Yoshim. Doi) Jaklitsch & Voglmayr, T. albofulvum (Berk. & Broome) Jaklitsch & Voglmayr, T. atrogelatinosum (Dingley) Jaklitsch & Voglmayr, T. corneum (Pat.) Jaklitsch & Voglmayr, T. cornu-damae (Pat.) Z.X. Zhu & W.Y. Zhuang, T. flaviconidium (P. Chaverri, Druzhinina & Samuels) Jaklitsch & Voglmayr, T. hamatum (Bonord.) Bain., T. hunua (Dingley) Jaklitsch & Voglmayr, T. patella (Cooke & Peck) Jaklitsch & Voglmayr, Hypocrea patella f. tropica Yoshim. Doi, T. polysporum (Link) Rifai, T. poronioideum (A. Möller) Samuels T. semiorbis (Berk.) Jaklitsch & Voglmayr, T. sulphureum (Schwein.) Jaklitsch & Voglmayr, and T. tropicosinense (P.G. Liu) P.G. Liu, Z.X. Zhu & W.Y. Zhuang.
RESUMO
Trichoderma aggressivum sp. nov. and T. aggressivum f. europaeum f. nov. are described. These forms cause the green mold epidemic in commercially grown Agaricus bisporus in North America and Europe, respectively. In the literature they have been reported as T. harzianum biotypes Th 4 and Th 2, respectively. They are strongly separated from their closest relative, T. harzianum, in sequences of the ITS-1 region of nuclear rDNA and an approximately 689 bp fragment of the protein coding translation elongation factor gene (EF-1α). They are distinguished from the morphologically similar T. harzianum and T. atroviride (the latter also known as biotype Th 3) most readily by rate of growth. Of these, only T. harzianum grows well and sporulates at 35 C, while T. atroviride is the slowest growing. Trichoderma aggressivum f. aggressivum and f. europaeum are effectively indistinguishable morphologically although they have subtly different growth rates at 25 C on SNA and statistically significant micromorphological differences. Based on findings of this study, descriptions of T. harzianum and T. atroviride are expanded. A key to Trichoderma species commonly found associated with commercially grown A. bisporus is provided.
RESUMO
Petri disease, or black goo, is a serious disease of vines in most areas where grapevines are cultivated. The predominant associated fungus is Phaeomoniella chlamydospora (Chaetothyriales). Several species of Phaeoacremonium (Pm.) also are associated, of which Pm. aleophilum is the most common. Although no teleomorph is known for Phaeoacremonium, the genus Togninia previously has been linked to phaeoacremonium-like anamorphs. To investigate the possible anamorph-teleomorph connection of Phaeoacremonium to Togninia, anamorphs of Togninia minima, T. fraxinopennsylvanica and T. novae-zealandiae morphologically were compared with Pm. aleophilum and some representative cultures were mated in all combinations. Although no interspecies mating proved fertile, matings between isolates of Pm. aleophilum produced a Togninia teleomorph within 3-4 weeks. Certain field isolates of Pm. aleophilum commonly produced the teleomorph, demonstrating that both mating types can occur in the same vine and thus also explaining the genetic diversity observed for this fungus in some vineyards. To elucidate the phylogenetic relationships among these taxa, isolates were subjected to sequence analysis of the nuclear ribosomal internal transcribed spacers (ITS1, ITS2) and the 5.8S rRNA gene, as well as portions of the translation elongation factor 1 alpha (EF-1α) gene. The generic placement of teleomorphs within Togninia (Calosphaeriales) further was confirmed via phylogenetic analyses of 18S small subunit (SSU) DNA. From these sequences, morphological and mating data, we conclude that T. minima is the teleomorph of Pm. aleophilum, and that it has a biallelic heterothallic mating system. An epitype and mating type tester strains also are designated for T. minima.
RESUMO
Trichoderma brevicompactum, a new species, was isolated from soil or tree bark in North, Central and South America, including the Caribbean Islands, and southwestern and southeastern Asia. Morphological and physiological characters, the internal transcribed spacer regions of the rDNA cluster (ITS1-5.8SrDNA-ITS2) and partial sequences of translation elongation factor 1-alpha (tef1) are described. Trichoderma brevicompactum is characterized by a pachybasium-type morphology, morphologically resembling other small-spored species referable to Trichoderma section Pachybasium but with essentially subglobose conidia. It is most closely related phylogenetically to Hypocrea lutea, from which it differs in morphological and physiological characters.
RESUMO
Ophiocordycipitaceae is a diverse family comprising ecologically, economically, medicinally, and culturally important fungi. The family was recognized due to the polyphyly of the genus Cordyceps and the broad diversity of the mostly arthropod-pathogenic lineages of Hypocreales. The other two cordyceps-like families, Cordycipitaceae and Clavicipitaceae, will be revised taxonomically elsewhere. Historically, many species were placed in Cordyceps, but other genera have been described in this family as well, including several based on anamorphic features. Currently there are 24 generic names in use across both asexual and sexual life stages for species of Ophiocordycipitaceae. To reflect changes in Art. 59 in the International Code of Nomenclature for algae, fungi, and plants (ICN), we propose to protect and to suppress names within Ophiocordycipitaceae, and to present taxonomic revisions in the genus Tolypocladium, based on rigorous and extensively sampled molecular phylogenetic analyses. When approaching this task, we considered the principles of priority, monophyly, minimizing taxonomic revisions, and the practical utility of these fungi within the wider biological research community.
RESUMO
The new rules formulated in Article 59 of the International Code of Nomenclature for algae, fungi, and plants (ICN) will cause numerous, often undesirable, name changes, when only phylogenetically defined clades are named. Our task is to name fungal taxa and not just clades. Two suggestions are made here that may help to alleviate some disadvantages of the new system. (1) Officially an epithet coined in a list-demoted genus that is older than the oldest one available in the list-accepted genus would have to be recombined in the accepted genus. We recommend that individual authors and committees establishing lists of protected names should generally not recombine older epithets from a demoted genus into the accepted genus, when another one from pre-2013 is available in that genus. (2) Because the concepts of correlated teleomorph and anamorph genera are often incongruent, enforced congruence leads to a loss of information. Retaining the most suitable generic name is imperative, even when this is subordinated to another, list-accepted, generic name. Some kind of cryptic dual generic nomenclature is bound to persist. We therefore strongly recommend the retention of binomials in genera where they are most informative. With these recommendations, the upheaval of fungal nomenclature ensuing from the loss of the former Art. 59 can be reduced to an unavoidable minimum.
RESUMO
Verticillium fungicola, the type species of Verticillium sect. Albo-erecta, and related taxa were studied using morphological and molecular techniques. Sequences of the ITS region and SSU rDNA suggest that V. fungicola is very close to members of the genus Lecanicillium and unrelated to other species that were originally accommodated in the same section. New combinations in Lecanicillium are proposed for Verticillium fungicola and its var. flavidum at species rank, L. f. var. aleophilum is retained as a variety. These taxa can be distinguished from each other by optimum and maximum temperatures for growth, in addition to ITS sequence differences. Morphologically, L. flavidum is also distinct by repeated branching of the conidiophores, whereas the two varieties of L. fungicola have a simple conidiophore axis.
Assuntos
DNA Espaçador Ribossômico/química , DNA Ribossômico/genética , Verticillium/classificação , Verticillium/crescimento & desenvolvimento , DNA Fúngico/genética , DNA Espaçador Ribossômico/genética , Filogenia , Esporos Fúngicos/crescimento & desenvolvimento , Verticillium/genéticaRESUMO
A comprehensive phylogenetic classification of the kingdom Fungi is proposed, with reference to recent molecular phylogenetic analyses, and with input from diverse members of the fungal taxonomic community. The classification includes 195 taxa, down to the level of order, of which 16 are described or validated here: Dikarya subkingdom nov.; Chytridiomycota, Neocallimastigomycota phyla nov.; Monoblepharidomycetes, Neocallimastigomycetes class. nov.; Eurotiomycetidae, Lecanoromycetidae, Mycocaliciomycetidae subclass. nov.; Acarosporales, Corticiales, Baeomycetales, Candelariales, Gloeophyllales, Melanosporales, Trechisporales, Umbilicariales ords. nov. The clade containing Ascomycota and Basidiomycota is classified as subkingdom Dikarya, reflecting the putative synapomorphy of dikaryotic hyphae. The most dramatic shifts in the classification relative to previous works concern the groups that have traditionally been included in the Chytridiomycota and Zygomycota. The Chytridiomycota is retained in a restricted sense, with Blastocladiomycota and Neocallimastigomycota representing segregate phyla of flagellated Fungi. Taxa traditionally placed in Zygomycota are distributed among Glomeromycota and several subphyla incertae sedis, including Mucoromycotina, Entomophthoromycotina, Kickxellomycotina, and Zoopagomycotina. Microsporidia are included in the Fungi, but no further subdivision of the group is proposed. Several genera of 'basal' Fungi of uncertain position are not placed in any higher taxa, including Basidiobolus, Caulochytrium, Olpidium, and Rozella.
Assuntos
Fungos/classificação , Fungos/genética , Evolução Molecular , Filogenia , Terminologia como AssuntoRESUMO
In a continuation of studies started by de Ruiter et al. (1993), all known species of the Mortierella isabellina-group (Micromucor/Umbelopsis clade of O'Donnell et al. 2001) and a few other Mucorales and species of Mortierella were investigated by RFLP (including ITS1, 5.8S, ITS2 and the 5' end of the large subunit rDNA gene) and ITS1 sequence analyses. This monophyletic group is unrelated to Mortierella and is only distantly related to the core group of the Mucoraceae. M. longicollis falls outside the Umbelopsis clade. Molecular data resolved two subclades within the M. isabellina-group; however, they are not correlated with any differences in sporangial wall and shape, spore pigmentation and shape, or sporangiophore branching. Therefore we subsume all taxa in one genus, Umbelopsis. The new family Umbelopsidaceae and the new combinations U. isabellina, U. ramanniana, and U. autotrophica are proposed.
Assuntos
Mucorales/classificação , Mucorales/genética , Técnicas de Tipagem Micológica , DNA Fúngico/genética , DNA Espaçador Ribossômico/genética , Genes de RNAr , Mucorales/citologia , Filogenia , Polimorfismo de Fragmento de Restrição , Análise de Sequência de DNARESUMO
Fermentation processes for the biochemical reagents cerulenin and helvolic acid employ 'Cephalosporium caerulens,' an invalidly published designation that has been used for more than 40 years. However, its identity has never been critically examined because strains were unavailable from major culture collections. An authentic strain of C. caerulens', derived from the original strain KF-140, was recently found and compared to Sarocladium oryzae, another Acremonium-like fungus which also produces cerulenin and helvolic acid. Morphological comparisons, rDNA sequence data, and chromatography of secondary metabolites established that 'C. caerulens' and S. oryzae are conspecific. Sequence data from ribosomal DNA genes indicated S. oryzae belongs to the Hypocreales and is allied with members of the Ceratostomataceae, Scopinella species, Emericellopsis species and certain Acremonium-like anamorphs of uncertain familial relationships. At least two of the isolates of S. oryzae produced titres of cerulenin and helvolic acid similar to those of KF-140. This finding demonstrates that manufacture of cerulenin need not be limited to the original strain.
Assuntos
Acremonium/metabolismo , Ascomicetos/metabolismo , Cerulenina/metabolismo , Ácido Fusídico/análogos & derivados , Ácido Fusídico/metabolismo , Ascomicetos/classificação , Ascomicetos/genética , Ascomicetos/crescimento & desenvolvimento , Cerulenina/biossíntese , DNA Fúngico/genética , DNA Ribossômico , FilogeniaRESUMO
The monotype species of the genus Verticillium, Verticillium tenerum, is a synonym of the older name Sporotrichum luteo-album. Its purported teleomorph connection with 'Nectria' inventa is refuted and the preserved specimens of that species are considered as probably identical with Stephanonectria keithii (Bionectriaceae). V. luteo-album takes a unique position in the Glomerella clade of ascomycetes, as sister of the Verticillium-Plectosphaerella clade, which comprises plant-pathogenic species. V. luteo-album is not closely related to V. dahliae and its relatives, which are also situated in this clade. Conservation of the name Verticillium with V. dahliae as conserved type will be necessary to retain this generic name for the plant-pathogenic Verticillium species. In anticipation of this conservation, the new combination Acrostalagmus luteo-albus (syn. Sporotrichum luteo-album) is made.
Assuntos
DNA Espaçador Ribossômico/análise , Doenças das Plantas/microbiologia , Verticillium/classificação , DNA Fúngico/análise , DNA Ribossômico/genética , Filogenia , Verticillium/genética , Verticillium/crescimento & desenvolvimento , Verticillium/patogenicidadeRESUMO
The new species Umbelopsis dimorpha sp. nov. was isolated from a soil sample in the Red Hills area of Mt Richmond Forest Park, in the northern part of the South Island of New Zealand. It has two kinds of pale pinkish sporangia: (1) single-spored, indistinguishable from those of U. versiformis; and (2) multi-spored, similar to those of U. vinacea. ITS sequences place the species in the immediate vicinity of the former species.
Assuntos
Fungos Mitospóricos/classificação , Sequência de Bases , DNA Fúngico/química , Fungos Mitospóricos/genética , Fungos Mitospóricos/crescimento & desenvolvimento , FilogeniaRESUMO
The morphology of two soil-borne Verticillium species, V. dahliae and V. tricorpus, was studied on two semi-selective agar media, in the absence and presence of soil. Morphology of the fungi differed considerably between the media, with respect to presence and shape of microsclerotia, dark hyphae (i.e. short melanised hyphae attached to the microsclerotia) and dark mycelium (i.e. melanised mycelium throughout the colony). On modified soil extract agar (MSEA), a pectate based agar, V. dahliae always had globose to elongate microsclerotia, without dark hyphae or dark mycelium, whereas V. tricorpus always had dark hyphae or dark mycelium, and microsclerotia, whenever present, were globose to irregular in shape. On ethanol agar (EA), V. dahliae had large microsclerotia and abundant dark hyphae, whereas V. tricorpus did not form microsclerotia, but always abundant dark mycelium. For the first time we observed the formation of dark hyphae by V. dahliae to a great extent. In the presence of soil, most characteristics were less pronounced, and V. dahliae microsclerotia were smaller, but V. tricorpus produced large microsclerotia, even when they were absent in pure culture. Morphological characteristics suitable for discrimination between the two species on MSEA plates in the presence of soil were selected and tested with fresh isolates from agricultural fields. The two fungi could be distinguished using qualitative characteristics and microsclerotial size. Molecular analysis and morphology on potato dextrose agar confirmed all identifications made on soil dilution plates.